Minimally invasive system for manipulating intervertebral disc tissue

ABSTRACT

The present invention relates generally to intervertebral disc devices and methods and instrumentation for intervertebral disc procedures. An intervertebral disc repair and diagnostic device that is minimally invasive, actively guided, and provides direct and consistent access to the inner surface of the posterior anulus, which will not unintentionally exit the posterior anulus and cause harm to the spinal cord, is provided.

RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No.10/020,507, filed Dec. 11, 2001, now U.S. Pat. No. 6,821,276, which iscontinuation-in-part of U.S. application Ser. No. 09/642,450, filed Aug.18, 2000, now U.S. Pat. No. 6,482,235 and claims priority under 35U.S.C. §119(e) to U.S. Provisional Appl. No. 60/298,605, filed Jun. 14,2001, all herein incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to devices and instrumentationfor intervertebral disc diagnosis and treatment, and methods thereof.

2. Description of the Related Art

An intervertebral disc performs the important role of absorbingmechanical loads while allowing for constrained flexibility of thespine. The disc is composed of a soft, central nucleus pulposussurrounded by a tough, woven anulus fibrosis. Herniation is a result ofa weakening in the anulus. Symptomatic herniations occur when weaknessin the anulus allows the nucleus to bulge or leak posteriorly toward thespinal cord and major nerve roots. The most common symptoms ofherniation include pain radiating along a compressed nerve and lowerback pain, both of which can be crippling for the patient. Herniation,and the resulting dehabilitating symptoms, are of significant medicalconcern in the United States because of the low average age ofdiagnosis. Indeed, over 80% of patients in the United States diagnosedwith herniation are under the age of 59.

Information regarding anular thickness, internal dimensions of the discspace normally occupied by the nucleus, and the location of anularapertures and lesions in relation to the vertebral endplates and lateralwalls of the anulus facilitates accurate diagnosis and treatment ofintervertebral disc conditions. For example, medical proceduresinvolving the implantation of an artificial nucleus or anularaugmentation depend on this information for accurate sizing of suchimplants. Also important are safe, dependable, and minimally invasivemethods and devices for the manipulation of anular and nuclear tissue,especially along the inner wall of the posterior anulus. For example,tissues in the anulus and nucleus are commonly removed or manipulatedduring the implantation of artificial discs either to clear a path forthe insertion of other types of prosthetic devices or as part of adiscectomy procedure.

Specialized tools have evolved for the surgical treatment ofintervertebral discs in the lumbar, cervical, and thoracic spine, whichhave suffered from tears in the anulus fibrosis or herniation of thenucleus pulposus. These tools are well-known in the prior art. Thedevices of the prior art, however, are designed for specific procedures,including complete discectomies (as opposed to partial discectomy orminute removal of tissue) and the installation of vertebral fusionimplants. Accordingly, these devices cannot be used to manipulate anularand nuclear tissue in a precise and minimally invasive manner. Moreover,such devices are typically designed to access the disc using an anteriorapproach, i.e., through the abdomen. Although an anterior surgicalapproach provides direct access to intervertebral discs, it is highlyinvasive to the abdominal organs. Thus, surgery is typically morecomplicated and time consuming. A direct posterior approach is notanatomically practicable because the spinal cord and its surroundingbony protective sheath lies directly in front of each vertebral disc. Anposterior-lateral aspect approach is the least invasive of these methodsbut provides limited and oblique access to the disc and its interior.Depending upon the surgical necessities involved, several methods ofpercutaneous disc tissue manipulation are available, includingchemonucleolysis (e.g., U.S. Pat. No. 4,439,423), laser (e.g., U.S. Pat.No. 5,437,661), manual, focused energy, ultrasonic disruption (e.g.,U.S. Pat. No. 5,772,661), arthroscopy and endoscopy.

Endoscopic instrumentation has evolved over the past 25 years andpermits viewing, irrigation, suction, and cutting. Probes that permitautomated percutaneous suction such as nucleotomes or cylindricallyhoused rotating cutting means, such as debreders, provide gross butefficient removal of disc tissue. Varying tip profiles control theamount and direction of tissue resection as well as the likelihood ofdamage to surrounding tissue. These devices tend to be limited by thesize of the cannula which houses the instrumentation and its ability tomaneuver around vertebral bodies and delicate tissues of the spine.

Hand tools for use in the spine are also well known and can be insertedthrough cannulae or freely guided by hand. These tips may be blades,burs, rongeurs, curettes or forcep-like “graspers” that are capable ofpinching of small amounts of material. To the extent that theseinstruments can access the various tissues, these devices provide goodtactical feedback and control. However, if used in an antero-lateralspinal approach, these tools are generally limited by the indirectapproach necessitated by the laminae and spinous processes of theadjacent vertebrae, and thus, access to tissues is substantiallyhampered.

Some intervertebral disc devices have been designed with flexible tipsthat are designed not to perforate or deflect off of the interiorsurface of the disc. Unfortunately, such tips deflect off of healthydisc tissue only, not the pathological tissue that caused the need forthe surgery in the first place. Thus, such instrumentation can exit theanulus and cause considerable damage to the surrounding tissues andspinal cord. Also, the flexible probe tips on some instruments whichpermit access to remote locations within the disc can only do so bysacrificing direct control because the devices are passively guided orblindly “snaked” within the disc. Accordingly, delicate and precise workwithin a disc is not possible with such instruments.

Among other disadvantages, the devices and methods of the prior art aretypically invasive and destructive to surrounding tissue, frequentlycausing disc infection and nerve root injury. Moreover, such devices areunable to precisely manipulate disc material along the posterior anulusin a minimally invasive manner. Accordingly, there is a need for anintervertebral disc diagnostic and manipulation device which is capableof performing delicate and precise work within a disc, especially alongthe posterior anulus and between anular lamella.

SUMMARY OF THE INVENTION

The current invention relates generally to devices and instrumentationfor intervertebral disc diagnosis and treatment, and methods thereof. Inseveral embodiments, the present invention provides for a minimallyinvasive and actively guided intervertebral disc repair and diagnosticdevice. This device provides direct and consistent access to the innersurface of the posterior anulus and will not unintentionally exit theposterior anulus and cause harm to the spinal cord. One skilled in theart will understand that this device is not limited to intervertebraldisc applications, but includes medical procedures in which a minimallyinvasive, actively guided device for diagnosis, repair or treatment isdesired. These procedures include, but are not limited to, arthroscopic,endoscopic, and endovascular applications. Further, one skilled in theart will appreciate that, in many embodiments, this invention may beused percutaneously or intralumenally.

Various embodiments of the invention may be guided by tactile feedbackor through active viewing. Also, various embodiments may be used inconjunction with medical imaging technologies, including MRI,ultrasound, or fluoroscopy. Further, several embodiments of theinvention having radiopacity or selective radiopacity may be used inconjunction with imaging methods for guidance and/or to facilitatemeasurement of organs or tissues.

Various embodiments of the current invention are particularlyadvantageous because they provide active controlled direction of theworking end of the instrument within the anulus or nucleus. Further,several embodiments provide access to the posterior portion of theanulus using a posterior surgical approach. In various embodiments,access to the posterior anulus, via circumferential navigation of theinstrument as it is deflected from the lateral, anterior, oppositelateral, and finally to the posterior anulus, is avoided. This isadvantageous because circumferential deflection of the working end ofthe instrument within the anulus can result in the tip of the instrumentpassing through a fissure in the posterior anular surface and outward tothe spinal cord. This can occur because the circumferential navigationfrom a typical posterior surgical approach eventually directs the tipperpendicular to the posterior anular surface, which may contain lesionslarge enough to allow protrusion of the tip directly through to thespinal cord.

There is provided in accordance with one aspect of the presentinvention, a device for treating the spine. The device comprises anelongate guide having a longitudinal axis. An axially moveable actuatoris carried by the guide. A probe is movable with the actuator, and adeflection surface is carried by the guide. Axial movement of theactuator causes the probe to advance along the deflection surface andextend away from the guide at an angle to the longitudinal access of theguide.

In one implementation of the invention, the guide comprises an elongatetubular body having at least one lumen extending therethrough. Theactuator extends through at least a portion of the guide. The probe maycomprise an elongate flexible body, attached to the actuator. The probemay be biased in a nonlinear configuration. In one embodiment, the probecomprises a nickel titanium alloy.

In accordance with another aspect of the present invention, there isprovided a method of treating a disc in the spine. The method comprisesthe steps of advancing a device at least part way through an anulus. Aprobe is advanced laterally from the device in a first direction along aportion of the anulus.

In one application of the invention, the advancing a probe stepcomprises advancing the probe in between adjacent (anular lamella)layers of the anulus. In another application of the invention, theadvancing a probe step comprises advancing the probe along an interiorsurface of the anulus, between the anulus and the nucleus. The methodmay further comprise the step of repositioning the probe and advancingthe probe in a second direction along a second portion of the anulus.

In accordance with a further aspect of the present invention, the methodadditionally comprises the step of introducing media through thedelivery device and into the disc. In one application, the mediacomprises contrast media, to permit fluoroscopic visualization. Themedia may alternatively or additionally comprise a medication, and/or anucleus augmentation material. The method may additionally comprise thestep of introducing a prosthesis into the disc. The prosthesis may beintroduced by proximately retracting a push rod from a lumen in thedelivery device, and introducing the prosthesis into the disc throughthe lumen.

As will be appreciated by those of skill in the art, the presentinvention, therefore, provides a minimally invasive access pathway intothe anulus and/or nucleus of a vertebral disc. The pathway may beutilized to perform any of a wide variety of procedures, includingdiagnostic and therapeutic procedures, some of which will be identifiedbelow.

Several embodiments of this invention provide a new intervertebral discmanipulation and diagnostic device.

One or more embodiments disclosed herein provide a convenient, reliable,and accurate way to measure the anular thickness and the internaldimensions of the disc space normally occupied by the nucleus pulposus.

Several embodiments of this invention provide a device useful indetermining various disc dimensions in order to enable a surgeon to sizevarious implants and tools and facilitate their guidance within thedisc.

Various embodiments provide for the manipulation through an opening inthe anulus. Manipulation includes, but is not limited to, dissection,resection or ablation of disc tissue. The opening may be a singleiatrogenic hole, such as an anulotomy, a naturally occurring hole, or alesion in the anulus.

One or more aspects of the current invention prepare or manipulate disctissue in preparation for the insertion of an implant or otherinstruments.

Several embodiments of the present invention diagnose and manipulatedisc tissue with minimal invasiveness and risk of unintended passage ofthe device outside of the posterior anulus in the direction of thespinal cord or other sensitive areas proximal thereto.

Various aspects of this invention permit direct access to the interioraspect of anulus via an anulotomy.

Several embodiments of invention provide an intervertebral discmanipulation and diagnostic device wherein the travel of the working endof the device is parallel to the lamellae of the anulus.

This disclosure utilizes particular orthopedic references, nomenclature,and conventions. Accordingly, several background figures anddescriptions are included to aid in the understanding of the environmentunder which specific embodiments of the invention may be used. In thisdescription and the following claims, the terms “anterior” and“posterior”, “superior” and “inferior” are defined by their standardusage in anatomy, i.e., anterior is a direction toward the front(ventral) side of the body or organ, posterior is a direction toward theback (dorsal) side of the body or organ; superior is upward (toward thehead) and inferior is lower (toward the feet).

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B show the general anatomy of a functional spinal unit345. FIG. 1A is a view of a transverse section. FIG. 1B is a view of asagittal section. FIG. 1C shows the same functional spine unit with adefect in the anulus, which may have been created iatrogenically, as inthe performance of an anulotomy, or may be naturally occurring.

FIGS. 2A and 2B are front and side views of a device in accordance withthe present invention.

FIG. 3 is an isometric view of the distal end of the device.

FIG. 4 is a side view of the depth stop components of the deviceincluding depth-measuring markings, the depth stop adjustment knob, andthe depth stop body.

FIG. 5 is a side view of the delivery cannula, cannula handle andintradiscal tip.

FIG. 6 is a side view of the advancer, with a ring-handle.

FIG. 7 is a cross-sectional view of the device with the intradiscal tippositioned within an anulotomy. The probe and depth stop are bothretracted, and the distal end of the device has been inserted to a depthbeyond the anterior aspect of the posterior anulus.

FIG. 8 depicts the probe of the device advanced relative to its startingposition in FIG. 7 above.

FIG. 9 depicts the intradiscal tip of the device with the probe restingon the inner surface of the posterior anulus.

FIG. 10 depicts the device with the depth stop advanced to the posteriorsurface of the posterior anulus.

FIG. 11A is a side view of the intradiscal tip of the device showing avariation of the probe tip. In this variation, the trailing edge of thereverse-curved tip has been sharpened. In FIG. 11B, the same intradiscaltip is shown with the probe advanced from its initial retractedposition.

FIG. 12 is a top view of the probe from FIGS. 11A and 11B shownunformed. The probe is shown as it would appear prior to forming, if itwere formed from a flat sheet of material, sharpened along one edge.

FIG. 13A is a side view of the intradiscal tip of the device, showing avariation of the probe tip. In this variation, the distal end of thereverse-curved tip is spaced further distally from the distal end of thedevice than that of the probe depicted in FIGS. 11 a–b. In FIG. 13B thesame device is shown with the probe advanced from its initial retractedposition.

FIG. 14 is a top view of the probe from FIGS. 13A and 13B shownunformed. The reverse curve that forms the distal tip of the probe isshown as it would appear prior to forming, if it were formed from a flatsheet of material.

FIG. 15A is a side view of a variation of the probe tip. In thisvariation, the tip of the reverse curve has two additional flanges ofmaterial on either side of the curve. The combination of tip elementsforms a scoop. In FIG. 15B the same device is shown with the probeadvanced from its initial retracted position.

FIG. 16 is a top plan view of the probe from FIGS. 15A and 15B shownunformed. The two side flanges and the reverse curve that forms thedistal tip of the probe are shown as they would appear prior to forming,if they were formed from a flat sheet of material.

FIG. 17A is a top view, and FIG. 17B is a side view of the distal end ofthe device of an embodiment of the invention. The probe includes anablation unit, control wires, and a tube, mounted to the probe proximalof the distal tip. The anvil of the device has material removed in itscentral area to allow the retraction of the tube and control wires intothe device.

FIG. 18 is a transverse view of the intervertebral disc wherein thedevice is being used to measure the anterior to posterior distance fromthe anulotomy to the inner aspect of the anterior anulus.

FIG. 19 is a transverse view of the intervertebral disc wherein theprobe is advanced from the anulotomy to the far lateral corner.

FIG. 20 is a transverse view of the intervertebral disc wherein theprobe is advanced from the anulotomy to the near lateral corner.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

In one aspect of the invention, there is provided a guide such as ahollow delivery cannula having a distal end and a proximal end. Theguide is dimensioned to fit within a small anulotomy as might be createdby a surgeon or through a naturally occurring hole or lesion in theanulus. An advancer, push rod, or actuator is axially moveably carriedby the guide, and coupled to a flexible probe member. The flexible probemember has a proximal end connected to the advancer and distal endconnected to or formed into a probe tip.

The probe is advanceable outwardly from the distal end of the cannulavia axial movement of the advancer within the cannula. In theillustrated embodiment, the probe member exits through a slot having acurved pathway or deflection surface located at the distal end of thecannula and can be advanced outwardly therefrom generally at an angle ofbetween about 30 to about 150 degrees relative to the cannula'slongitudinal axis. Accordingly, when the distal end of the cannula isproperly inserted within the anulotomy at sufficient depth, the probetravels along a path that is parallel to and along the surface of or inbetween the anular lamellae. The probe may be retracted via reversingthe action (e.g. proximal retraction) of the advancer.

A means for measuring the distance advanced by the probe is associatedwith the probe and cannula. Any of a variety of measurement indicia maybe used, such as calibrated markings on the advancer visible through orproximal to the cannula. An indicator for measuring the distanceadvanced by the cannula within the anulotomy or lesion may also beincluded. For example, a calibrated depth stop may be affixed in aslideably adjustable manner to the delivery cannula.

The probe tip at the distal end of the probe member may be an integralpiece of the probe wherein the tip and the probe are of a unitaryconstruction. Alternatively, the tip may be secured, either releasablyor permanently to the probe. The tip can be blunt enabling it toforcibly part the tissue without cutting it (blunt dissection) or besharpened to present a sharp dissecting blade surface (sharpdissection).

The tip may also be constructed in a backwardly curved manner facingback towards the longitudinal axis of the cannula and with its reversefacing edge sharpened to facilitate resection or sharp dissection as itis retracted. This curved shape also serves to present a blunt profilethat is less likely to perforate the anulus as it is advanced, even inthe presence of uneven or degenerated anular tissue. Alternatively, thecurved resection tip or blade may be formed as a multi-sided scoop witha concave trailing surface and convex leading surface such that itpresents a blunt frontal profile even when advanced off-angle into theanulus or toward a vertebral endplate.

In another embodiment, the tip may be configured to house an ablationelement. This element may be preferentially insulated on particularsurfaces of the probe and/or tip to minimize unwanted damage to adjacenttissues. For example, the surface of the probe or tip facing an inneraspect of the anulus may be insulated to prevent unwanted travel throughor harm other portions of the anulus, nucleus and vertebral endplates.Ablation energy is instead directed to the targeted tissue adjacent tothe probe tip and not the endplates or tissue facing the insulted sideof the probe tip.

FIG. 1A is an axial view along the transverse axis M of a vertebral bodywith the intervertebral disc 315 superior to the vertebral body. Axis Mshows the anterior (A) and posterior (P) orientation of the functionalspine unit within the anatomy. The intervertebral disc 315 contains theanulus fibrosus (AF) 310 which surrounds a central nucleus pulposus (NP)320. Also shown in this figure are the left 370 and right 370′transverse spinous processes and the posterior spinous process 380.

FIG. 1B is a sagittal section along sagittal axis N through the midlineof two adjacent vertebral bodies 350 (superior) and 350′ (inferior).Intervertebral disc space 355 is formed between the two vertebral bodiesand contains intervertebral disc 315, which supports and cushions thevertebral bodies and permits movement of the two vertebral bodies withrespect to each other and other adjacent functional spine units.

Intervertebral disc 315 is comprised of the outer AF 310 which normallysurrounds and constrains the NP 320 to be wholly within the borders ofthe intervertebral disc space. Axis M extends between the anterior (A)and posterior (P) of the functional spine unit. The vertebrae alsoinclude facet joints 360 and the superior 390 and inferior 390′ pediclethat form the neural foramen 395.

Referring FIG. 2 a, the device 10, a cannula handle 35, and a ringhandle 45 are positioned such that the device 10 may be operated by onehand, i.e. utilizing the thumb, index, and ring fingers to position thedevice 10 and advance and retract the probe member 20. However, any of avariety of proximal handpieces can alternatively be used, includingtriggers, slider switches, rotatable knobs or other actuators to advanceand retract the probe 20 as will be apparent to those of ordinary skillin the art in view of the disclosure herein.

In FIG. 5 the cannula handle 35 is secured to the proximal end 32 of anouter delivery cannula 30. Outer delivery cannula 30 extends from theproximal end 32 to a distal end 34 which is provided with an intradiscaltip 50. Delivery cannula 30 functions as a guide for the axialreciprocal movement of a push rod 40 as will be discussed. Deliverycannula 30 may, therefore, be provided in the form of an elongate tubehaving a central lumen for receiving push rod 40 therethrough.Alternatively, the guide may comprise a nontubular structure, in anembodiment in which the push rod travels concentrically over oralongside the guide.

The delivery cannula 30 may be manufactured in accordance with any of avariety of techniques well known in the medical device arts. In oneembodiment, the cannula 30 comprises a metal tube such as stainlesssteel or other medical grade metal. Alternatively, the cannula 30 maycomprise a polymeric extrusion such as high density polyethylene, PTFE,PEEK, PEBAX, or others well known in the medical device arts.

In general, the axial length of the delivery cannula 30 will besufficient to reach the desired treatment site from a percutaneous orsmall incision access through the skin. Lengths within the range fromabout 10 centimeters to about 30 centimeters are contemplated, with alength from a proximal end 32 to distal end 34 within the range of fromabout 14 to about 20 centimeters contemplated for most posterior lateralaccess pathways. The length may be varied depending upon the intendedaccess pathway and patient size.

Preferably, the outside diameter of the delivery cannula 30 is nogreater than necessary to accomplish the intended functions disclosedherein. In general, outside diameters of less than one centimeter arepreferred. In typical embodiments of the present invention, the deliverycannula 30 has an outside diameter of no greater than approximately 5millimeters.

Referring to FIG. 6, the push rod or advancer 40 comprises an elongatebody 42 having a proximal end 44 and a distal end 46. Push rod 40 maycomprise a solid rod or tubular component as may be desired, dependingupon the construction materials and desired physical integrity. In oneembodiment, the push rod 40 comprises a solid metal rod, such asstainless steel or other suitable material. Alternatively, a polymericextrusion using any of a variety of known medical grade polymers may beused.

Push rod 40 is preferably dimensioned to extend throughout the length ofthe delivery cannula 30, so that the probe 20 is fully extended from theintradiscal tip 50 when the ring handle 45 is brought into contact withthe cannula handle 35 or other stop surface.

The device 10 may optionally be provided with one or more axiallyextending lumens, for placing the proximal end of the device 10 in fluidcommunication with the distal end, for any of a variety of purposes. Forexample, one or more lumens may extend through the push rod 40.Alternatively or in addition, the outside diameter of push rod 40 may bedimensioned smaller than the inside diameter of the delivery cannula 30to create an annular space as is well understood in the catheter arts. Afirst lumen may be utilized for introduction of radiopaque dye tofacilitate visualization of the progress of the probe 20 and or distalend of the device 10 during the procedure. The first lumen or secondlumen may be utilized to introduce any of a variety of media such assaline solution, or carriers including any of a variety of medicationssuch as anti-inflammatory agents e.g., steroids, growth factors e.g.,TNfα antagonists, antibiotics, and functional proteins and enzymes e.g.,chympopapain. A lumen may also be utilized to aspirate material such asnucleus pulposus, and/or to introduce nucleus augmentation materialduring or at the end of the procedure.

Referring to FIG. 7, the distal end 34 of device 10 is shown in crosssection. Distal end 34 includes an axially moveable probe member 20, anouter delivery cannula 30 and an advancer or inner push rod 40. A curvedpassage or slot 60 is proximal an intradiscal tip 50 of the deliverycannula 30. The passage or slot 60 includes a curved distal deflectionsurface which acts to deflect the probe member 20 in a path that isroughly parallel to the lamellae of the posterior anulus fibrosus 310 asthe probe member 20 is advanced outwardly from the curved slot 60 andinto the disc 315 by the advancer 40.

The distal end 34 of the cannula 30 may be provided with any of avariety of constructions, depending upon the mode of deflection of theprobe 20. In the illustrated embodiment, the distal end 34 is providedwith a cap 52 which contains the deflection surface 62 therein. Cap 52may be molded from any of the polymeric materials identified elsewhereherein, and secured to the distal end 34 by adhesive bonding,interference fit, or other conventional securing technique. Cap 52 hasan atraumatic distal surface 50, which may comprise the distal end ofcap 52, or may include a coating or layer of an atraumatic material suchas silicone, carried by the cap 52.

Any of a variety of alternative deflection surfaces may be used,depending upon the desired distal tip design. For example, the distalmolded cap 52 may be eliminated, and the deflection surface formedinstead by an inside surface of the tubular cannula 30. This may beaccomplished by providing two opposing axial slots extending proximallyfrom the distal end 34 of the cannula 30 to isolate two opposing axialribbons on the distal end 34. A first one of the ribbons is severed andremoved, while the second one is curved across the central axis of thecannula 30 to provide a curved deflection surface.

Alternatively, the deflection surface may be eliminated in certaincircumstances. For example, in the procedure illustrated in FIG. 7, thedevice is inserted through a defect in the posterior annulus at an anglerelative to the desired treatment plane that requires the probe 20 toexit the device at a corresponding angle in order to advance the probealong the surface of or within the annulus as shown (e.g., within orparallel to the desired treatment plane). However, by moving the accesspath through the annulus roughly 80–90 degrees counterclockwise asviewed in FIG. 7, the longitudinal axis of the device 10 can bepositioned coplanar or parallel to the posterior interior surface of theannulus or other desired treatment plane. In this orientation, the probeis desirably launched axially out of the end of the cannula 30, todissect a space for subsequent annulus patch implantation.

The foregoing axial launch embodiment of the invention may be utilizedthrough the naturally occurring defect. However, the axial launch deviceis more likely to find application through an iatrogenic access pathway,created through the annulus spaced apart from the natural defect suchthat the longitudinal axis of the iatrogenic access is substantiallyparallel (e.g., no more than about+/−20 degrees) from the plane in whichthe natural defect resides.

As a further alternative, the probe 20 may be laterally deflectable inresponse to manipulation of a deflection control at the proximal end ofthe device 10. For example, the probe 20 in one construction comprises aflexible metal or polymeric ribbon, extending from the distal end of theadvancer 40 or other axial support. An axially extending steeringelement is attached to the probe 20. Generally the steering element willbe attached near the distal end of the probe 20. Axial proximal ordistal movement of the steering element relative to the advancer 40 willcause a lateral deflection of the probe 20.

The radius of curvature of the deflection can be controlled in a varietyof ways as will be apparent to those of skill in the art in view of thedisclosure herein, such as by varying the lateral flexibility of theprobe 20, and the attachment point of the steering element to the probe20. Due to the differing physical requirements of devices under tensioncompared to compression, the cross section of the device may beminimized if the steering element is a pull wire or ribbon such thataxial proximal retraction of the pull wire relative to the probe 20causes a lateral deflection of the probe 20. The lateral deflection canbe coordinated with the extent of distal advance to cause the probe tofollow the desired curved path either by mechanics in the proximalhandpiece, or by the clinician. For this purpose, the proximal handpiececan be provided with any of a variety of controls, such as sliderswitches or rotatable levers or knobs to allow the clinician to controldeflection as well as distal (and lateral) advance.

In an alternate construction, the probe launches axially from the distalend 34 of the cannula or other guide 30, but curves under its own biasto travel in a lateral arc and slide along the posterior annulus orother desired surface. This may be accomplished by constructing theprobe from a nickel—titanium alloy such as Nitinol and providing it witha lateral pre bent orientation. The probe is restrained into an axialorientation within the cannula 30, but extends laterally under its ownbias as it is advanced distally from an opening in the distal end of thecannula 30.

The probe member 20 in the illustrated embodiment may be formed from asuperelastic nickel titanium alloy, or any other material with suitablerigidity and strain characteristics to allow sufficient deflection bydeflection surface 62 without significant plastic deformation. The probemember 20 can be formed from an elongated sheet, tube, rod, wire or thelike. Probe 20 may also be constructed in various cross-sectionalgeometry's, including, but not limited to hemicircular, semicircular,hollow, and rectangular shapes.

A probe tip 80 at the distal end of the probe member 20 can be used todissect between the anulus 310 and nucleus 320, to dissect betweenlayers of the anulus 310, or to dissect through the nucleus. The probetip 80 can be constructed of the same material as the probe member 20 oranother suitable material for the purposes of cutting or presenting ablunt rounded surface. A sharpened surface on the distal edge of theprobe member 20 forming the probe tip 80 can be used to dissect a pathto enable the insertion of an implant in the created space. Similarly, ablunted tip profile may be used to separate or disrupt anular lamellaand create an open space between the anulus 310 and nucleus 320 orwithin the nucleus 320 itself.

The probe tip 80 may also be provided with a backward curve as shown inFIGS. 11A and 11B. In this construction, a concave surface faces thelongitudinal axis of the device when deployed within the disc. The tip82 may be sharpened to facilitate resection or sharp dissection as it isretracted. This curved shape will also serve to present a blunt profileto reduce the risk of perforating the anulus 310 as it is advanced, evenin the presence of uneven or degenerated anular tissue. The curved tip80 may be formed in any of a variety of radii or shapes depending on theamount of material one desires to remove on each pass of the probemember 20 into the disc, as shown in FIGS. 13A and 13B. Alternatively,the resection tip 80 or blade may be formed as a multi sided concavescoop 81 having a cavity therein such that it presents a blunt convexfrontal profile even when advanced off-angle into the anulus 310 ortoward a vertebral endplate 350, as shown in FIGS. 15A and 15B. Also,the increased surface area of such a scoop 81 would serve to furtherfacilitate removal of disc tissue.

The distal end of device 10 is shown in FIG. 7 as inserted through adefect in the posterior anulus 300. Alternatively, the device 10 couldbe inserted through defects in the posterior-lateral, lateral, oranterior anulus 300. In these alternate positions, the probe tip 80 canbe advanced parallel to the lamellae of different regions of the anulus310. One of the many advantages of the curved, distal probe tip 80, asrepresented in several embodiments of the current invention, is itsminimal profile when the probe is in its retracted state relative to theouter cannula 30. In this state, depicted in FIG. 7, the curved tip 80fits around the distal end of intradiscal tip 50, only minimallyincreasing the size or profile of device 10. This minimizes the size ofthe defect in the anulus 300 necessary to allow proper insertion of thedistal end of device 10.

As demonstrated in FIGS. 11 and 13, various geometry's of the tip 80 canbe employed without increasing the necessary anular defect or anulotomy300 size for insertion of the intradiscal tip 50 of the device 10. Forexample, the larger radius of the probe tip 80 in FIG. 13 presents ablunter dissection profile when advanced from the intradiscal tip 50without necessitating a correspondingly larger anulotomy 300 for properinsertion of the device 10 into the disc. As the bluntness of probe tip80 is increased, it may be desirable to increase the stiffness of theprobe 20. This increased stiffness may be achieved in a variety of wayswhich can include, but is not limited to using a thicker or more rigidmaterial for forming probe; 20, or by using a curved cross-sectionalshape along the length of probe 20. These techniques may be used tostiffen all or a portion of the length of probe 20.

The probe tip 80 may also be coupled to an ablation unit for ablatingtissue, as shown in FIGS. 17A and 17B. The ablation unit can be attachedto the probe member 20 preferably on the side facing the interior of thedisc and proximal to the probe tip 80. In this configuration, the probemember 20 acts as a mechanical and thermal barrier minimizing unwantedablation in the direction opposite the ablation unit, i.e. in thedirection facing the interior aspect of the anulus. Ablation may beachieved using any of a variety of energy delivery techniques including,but not limited to light (laser), radio-frequency or electromagneticradiation in either unipolar or bipolar configurations, resistiveheating of the probe, ultrasound or the like.

An embodiment of a bipolar radio-frequency unit is depicted in FIG. 17.Power and control wires 91 may be deposited directly on to the probemember 20 as is known in the art. These wires act to connect RF elements90 to an external power source and control unit affixed to or incommunication with the advancer 40 and cannula 30. These elements 90serve to allow the conduction of current therebetween, resulting in aresistive heating of the tissue in the region of the probe tip 80. Theseelements 90 are shown proximal to the distal probe tip 80 of device 10,but may be positioned at any location along probe 20 and/or on probe tip80. Only two elements 90 are shown, however numerous elements may bepositioned at various locations along the entire length of the probe 20and be activated individually or multiplexed in pairs or groups toproduce a desired temperature profile or ablation within the disctissue.

Tube 92 is shown attached to probe 20 to provide an escape path forvapor and material ablated or for the infusion of fluids or gasses.These fluids or gasses may be added to alter the conductivecharacteristics of the tissue or may include various drugs, medications,genes or gene vectors or other materials to produce a desirabletherapeutic affect. Tube 92 is shown with a single distal orifice. Itmay alternatively comprise any number of side holes or channels toincrease the spread of fluids or gasses within the tissue or similarlyto remove such materials as required by the procedure. Axial lumen areprovided as needed to place the side holes or other apertures incommunication with the proximal end of the device 10. The ablation unitcould be activated as the probe member 20 is advanced through thetissues to create a cavity or activated as the probe member 20 isretracted after it has been advanced to a desired distance. Moreover,the power supplied to the ablation unit 90 could be varied according tothe instantaneous velocity of the probe member 20 in order to ablate amore uniform cavity within the disc.

Whether used to dissect, resect or ablate tissue within the disc, device10 may be used as part of an implantation procedure by creating a cavityor dissected region into which any of a variety of intradiscal implantsor medications may be inserted. This region may be between or withinanular layers 310, within the nucleus 320, or between the anulus 310 andnucleus 320. It may include a portion or the entirety of the nucleus.Increasing amounts of disc tissue may be removed by advancing andretracting the probe tip repeatedly at different depths within the disc.Intradiscal implants may be inserted independently using separateinstrumentation or along, through, or around probe 20. Suitable implantsinclude, among others, those disclosed in U.S. patent application Ser.No. 09/642,450 filed 8/18/200 entitled Devices and Methods of VertebralDisc Augmentation, the disclosure of which is incorporated in itsentirety herein by reference.

FIG. 7, 8, 9, and 10 depict an embodiment of the device 10 placed withinan anulotomy or defect of anulus 300, which can be used to measure thethickness of anulus 310. In FIG. 7, the distal portion of the cannula 30defined by the intradiscal tip 50 is inserted through the anulotomy ordefect 300 to a depth wherein the probe 20 is inserted just beyond theanterior border of the posterior anulus 310. In FIG. 8, the probe member20 is advanced out of cannula 30 and deflected by the deflection surfacein curved passage 60 of the intradiscal tip 50 at an angle nearlyperpendicular to device 10, causing the probe member 20 to advanceparallel to the inner surface of the posterior anulus 310. In this use,the probe 20 need only be advanced outward several millimeters.

In FIG. 9, device 10 is proximally retracted from the anulotomy 300until the probe 20 contacts the posterior anulus 310. In FIG. 10, aslideably adjustable depth stop 70 is carried by the cannula 30 andadvanced distally (anteriorly) until it contacts the exterior surface ofthe posterior anulus 310 and the probe member 20 is in contact with theinterior surface of the posterior anulus 310. The depth stop 70functions by abutting anular tissue or surfaces of the vertebral bodyadjacent to the anulotomy 300 which impede further entry of the cannula30 into the disc, such as may be determined by tactile feedback or underfluoroscopic visualization. FIG. 4 shows the depth stop adjustment knob105, calibrated measurement marks 100 and depth stop 70. The cannula 30or depth stop 70 may be marked with calibrated measurements 100 so thatthe distance between the intradiscal tip 50 at the point where the probemember 20 exits and the depth stop 70, can be determined. This distancecorresponds to the thickness of the anulus adjacent to the anulotomy300.

FIG. 18 depicts an embodiment of the device 10 placed within ananulotomy or defect in anulus 300 and being used to determine theanterior-posterior dimension of the nuclear space as defined by thedistance between the inner surfaces of the posterior anulus and theanterior anulus. Here, the probe member 20 and the adjustable depth stop70 are fully retracted. The probe 20 and advancer 40 may be eliminatedentirely in an embodiment intended solely for the anterior-posteriormeasurement described herein. The intradiscal tip 50 of the device 10 isadvanced through the anulotomy or defect in anulus 300 until the innersurface of the anterior anulus is reached and impedes further travel ofthe intradiscal tip 50. In this manner the device 10 is used to providetactile feedback of the disc's internal geometry. The adjustable depthstop 70 is then advanced distally toward the proximal exterior surfaceof the anulus or vertebral body and reading of the maximum depth reachedcan be obtained via calibrations on the proximal end of the device suchas on the cannula. Electronic or other means could also be employed tomeasure and display this distance. The posterior anular thickness valuecan be subtracted from this to yield the distance between the inneraspects of the posterior and anterior anulus.

FIGS. 19 and 20 depict an embodiment of the device 10 placed within ananulotomy or defect in anulus 300 and being used to determine thedistance between the left and right lateral interior surfaces of theanulus. In measuring the distance between the left and right lateralsurfaces of the anulus 310 the intradiscal tip 50 is inserted justbeyond the interior wall of the posterior anulus, the probe tip 80 isadvanced out of the curved passage 60 in the plane of the disc, i.e.parallel to the endplates, until tactile feedback from the advancer 40,indicates that lateral surface is resisting further advancement.Calibrated makings on the advancer 40 visible through or proximal to thecannula can then be used to determine this distance.

By rotating the device 10, while the probe member 20 is fully retracted,180 degrees and performing the same action in the lateral direction, asshown in FIG. 20, one can obtain the total distance between the interiorlateral surfaces. This method may be repeated at various depths withinthe disc by adjusting the depth stop 70. A similar method of using theprobe member 20 to tactically interrogate the interior of the disc maybe employed to dimension the distance between the vertebral endplatesand relative distances from the anulotomy 300 to the endplates. All ofthe foregoing measurements may be taken either using a scoop shapeddistal tip as shown, or a blunt, atraumatic tip without a scoop tominimize disruption of the nucleus.

Depth stop 70 may also be used to coordinate the dissection or resectionof a space within the disc with the placement of another intradiscalinstrument or implant. This method may be particularly useful forplacing an implant along an inner surface of the anulus fibrosus. Thethickness of the anulus as determined by any of the measurementtechniques described above may be used for setting depth stops on otherimplantation instruments used to place an implant along the anulus. Asan example, if the posterior anulus is measured to be 7 mm thick usingdevice 10, a depth stop may be set on an implantation instrument tolimit the penetration of this instrument into the disc to 7 mm oranother depth that is relative to 7 mm. This would allow for an implantplaced by this instrument to be inserted into a space previouslydissected within the disc by device 10 along the inner surface of theposterior anulus.

Probe 20 may be used as part of the placement of an intradiscal implantin any of a variety of ways. One advantageous use of the probe 20 can beachieved by detaching it from advancer 40 once probe 20 is in a desiredposition within the disc space. Implants may then be passed along,behind or in front of probe 20 into this desired position. Probe 20 maythen be removed from the disc space.

The measurement techniques described above may also be used to achievethe complete resection of the nucleus from the disc space. For example,a resection or ablation tip as described above may be passed repeatedlyinto the disc to the lateral borders of the nucleus. This process may berepeated at varying depths within the disc from the inner aspect of theposterior anulus to the inner aspect of the anterior anulus asdetermined by the depth stop.

While this invention has been particularly shown and described withreferences to preferred embodiments thereof, it will be understood bythose skilled in the art that various changes in form and details may bemade therein without departing from the scope of the inventionencompassed by the appended claims.

1. A method of manipulating a bodily tissue, wherein the tissue isenclosed by a definable outer layer of the same or different bodilytissue, the method comprising: locating an opening in the outer layer,wherein said outer layer comprises bony or spinal tissue; insertingwithin said opening to a point past the outer layer a distal end of ahollow cannula, said cannula having a proximal end and a distal end andhaving an elongated longitudinal axis, said cannula slideably housing anadvancer coupled to a probe member, said probe member having a proximalend connected to the advancer and said distal end of said probe memberconnected to a tip, said distal end of the probe member capable of beingadvanced and retracted through a curved slot at the distal end of thecannula via longitudinal movement of the advancer within said cannula;and advancing the advancer within the cannula and causing the probemember to be advanced outward from the curved passage at an anglebetween 30 and 150 degrees relative to the long axis of the cannula suchthat the probe tip travels and manipulates tissue parallel to theintersection of the tissue with the definable outer layer of tissue. 2.The method of claim 1, further comprising locating an opening in theouter layer of a tissue within an intervertebral disc.
 3. The method ofclaim 1, further comprising guiding said cannula.
 4. The method of claim3, wherein said cannula is guided by tactile feedback.
 5. The method ofclaim 3, wherein said cannula is guided by auditory signals or visualimages.
 6. The method of claim 5, wherein said auditory signals areobtained by ultrasound.
 7. The method of claim 5, wherein said visualimages are obtained by a method selected from the group consisting of:magnetic resonance imaging, ultrasound, and fluoroscopy.
 8. The methodof claim 1, wherein said opening is naturally occurring or iatrogenichole.
 9. The method of claim 1, further comprising inserting aprosthetic device beyond said opening in the outer layer.
 10. The methodof claim 1, further comprising ablating a target tissue.
 11. The methodof claim 1, wherein said bony or spinal tissue comprises intervertebraldisc tissue.
 12. The method of claim 1, wherein said bony or spinaltissue comprises anulus fibrosis.
 13. The method of claim 1, furthercomprising forcibly parting at least a portion of the tissue withoutcutting it.
 14. The method of claim 1, further comprising forciblycutting at least a portion of the tissue.
 15. The method of claim 1,further comprising aspirating fluid using one or more lumens locatedwithin said cannula.
 16. The method of claim 1, further comprisingdelivering material using one or more lumens located within saidcannula.